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Generic Wiring Harness for use with MBE9A4 ECU

MRP Without VAT:£535.04

MRP With VAT:£642.05

Coil Options

Crank Options

Instruction Sheets: LM9A4-ENG-01 Wiring and Relay Information


Generic Wiring Harness for use with MBE9A4


SBD have now produced a modular wiring harness system. This allows the user to immediately select the main engine harness and then choose the type of coil and crank adapters they wish to use from the list of options available.

We have a range of pre-designed adapters, which suit the coils that we sell and know all the characteristics for, so when purchasing a new ECU or upgraded map, these settings can be loaded. They are available for wasted spark coil pack or coil on plug*

We have a choice of crank adapters, which allow the use of a range of crank sensors to suit a popular range of engines and sensors we have in stock.

Injector connectors are fitted with a 2-way mini timer.

*Please note most MBE9A4s are built with amplifiers inside the ECU, if the coil selected has amps built in, the 9A4 has to built differently and cannot be altered after manufacture.
LM9A4-ENG-01 with connector detail

The relays have been designed to use a standard type relay available from any motor factor, in the picture shown you use a special base with locking terminals. These are designed to prevent issues that could occur with vibration when standard type relay bases were used. Each terminal locks itself to the pin of the relay and will only unlock when the base is pulled back, this makes a perfect vibration proof connection.
Note: older designs had individual locking terminals, each wire is colour coded & you will receive a simple diagram with the harness to show the colours.

SBD wiring harness relays
Coolant Temperature Sensor
We have fitted a mini-timer connector for the coolant sensor, this allows the use of the more commonly available & more widely used Bosch/Lucas type sensor. If your engine is not fitted with this sensor, they are available from us, part number WTS1.

Air Temperature Sensor
The air temperature sensor connector has a two-way mini-timer, which will connect to the Bosch/Lucas type sensor. We normally recommend that this measures ambient air temperature as opposed to being fitted to the air filter back plate which normally suffers from heat soak in most installations particularly rallying, sprinting, etc. where the car is kept stationary with a hot engine for periods of time. Only forced induction system must have the air temp sensor in the intake or engines where they are used for endurance events where the sensors are continually cooled by passing air. NOTE: a sensor once heat soaked takes on average up to 5-10 minutes of running in fresh air before it begins to measure a true incoming air temperature. There are various air temperature sensor options; AT1, AT2 and AT3, for more information please see the links below.

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Coil Options

Crank Options